The problem comes when you have to follow that opening scene with scene 2. The tension in your story is supposed to build. How do you follow that bang with something even bigger? If the bang at the beginning sets your story in motion, it can work because your character now has a goal and is struggling toward it. As she tries and fails and tries and fails, the tension increases.
But it isn’t enough to simply have more and more tension. In scene 1, the family hurries to load their car. The fact that they are in a hurry creates a certain amount of tension. In scene 2, the family races away from an approaching flood. Tension and floodwaters rise but it isn’t enough unless one scene causes or enables the next. In this example, it does.
Unfortunately, sometimes we write tense scenes that just don’t cause or enable the next scene. We use the excuse that we need to start the story with a bang. Or maybe we’re adding to the reader’s knowledge of the main character. Fabulous. But for your story to hold together, the scenes or chapters have to be strung together like beads.
To make sure your scenes do all that they should, do a Plot Dot Test. Take out a piece of paper and draw a line. This is your starting point. Read chapter or scene 1. Mentally note how much tension there is. This is ground zero. But Dot 1 on the line. Read the next scene/chapter. Does the tension go up? Then Dot 2 will be higher.
Can you state what in chapter 1 leads directly to chapter 2? Got it? Then you have the cause and effect and can connect Dots 1 and 2.
Work through your entire manusscript like this. At some points, your tension will drop. This is typical after your hero fails or succeeds to solve her problem (see above Dots 4/7/11). But if you have too many drops and you can’t connect several chapters, you’ve got a bit more work to do.